Your safest bet would be to order both the UTG mid and high riser mounts mentioned in my answer to you earlier, and then return the one you don't need.
Do not order the Bushnell riser as I don't think you won't be able to co-witness with it properly.

For those trying to use this with an AR, you will need a riser, there are two types that will work, a medium and a high. The basic cheap UTG one from Amazon is decent.

The Medium height riser below should put you in the zone for absolute co-witness. This means that the iron sights that come with the gun should line up exactly with the red dot.
Pros: only one point at which to aim, failure of your red dot requires no adjustment, you can see if your red dot is off, possibly a slightly better cheekweld
Cons: There is alot of sight in your red dot FOVhttps://www.amazon.ca/UTG-Medium-Profil ... =utg+riser

Conversely there is a high profile riser that should put you in the zone for lower 1/3 cowitness . This means that your iron sights are in the lower 1/3 of your red dot, and your red dot sits central in the scope above it
Pros: There is less sight visible in your red dot
Cons: possibly a bit more of a chin-weld than cheek as the sight is higher, you can't tell if your red dot goes out of calibrationhttps://www.amazon.ca/UTG-Profile-Riser ... =utg+riser

There is no fundamentally better option, it is just personal preference. In a gun like the smith wesson mp sport 2, the front sight post is fixed, so you have to decide if you want to have that front sight post right in the centre of your red dot or in the lower 1/3 of the scope when you look through it. I myself prefer lower 1/3 if the front sight post is fixed, I like a little bit of space underneath the red dot for target identification, but overall I like the ergonomics of absolute if the back-up iron sights are able to be folded down. It's just personal preference and doesn't actually matter alot because these are meant to be shot with both eyes always open, with body facing square to target, so that really it makes very little difference which you choose in terms of overall target visibility.

For those trying to use this with an AR, you will need a riser, there are two types that will work, a medium and a high. The basic cheap UTG one from Amazon is decent.

The Medium height riser below should put you in the zone for absolute co-witness. This means that the iron sights that come with the gun should line up exactly with the red dot.
Pros: only one point at which to aim, failure of your red dot requires no adjustment, you can see if your red dot is off, possibly a slightly better cheekweld
Cons: There is alot of sight in your red dot FOVhttps://www.amazon.ca/UTG-Medium-Profil ... =utg+riser

Conversely there is a high profile riser that should put you in the zone for lower 1/3 cowitness . This means that your iron sights are in the lower 1/3 of your red dot, and your red dot sits central in the scope above it
Pros: There is less sight visible in your red dot
Cons: possibly a bit more of a chin-weld than cheek as the sight is higher, you can't tell if your red dot goes out of calibrationhttps://www.amazon.ca/UTG-Profile-Riser ... =utg+riser

There is no fundamentally better option, it is just personal preference. In a gun like the smith wesson mp sport 2, the front sight post is fixed, so you have to decide if you want to have that front sight post right in the centre of your red dot or in the lower 1/3 of the scope when you look through it. I myself prefer lower 1/3 if the front sight post is fixed, I like a little bit of space underneath the red dot for target identification, but overall I like the ergonomics of absolute if the back-up iron sights are able to be folded down. It's just personal preference and doesn't actually matter alot because these are meant to be shot with both eyes always open, with body facing square to target, so that really it makes very little difference which you choose in terms of overall target visibility.

Thanks @DealPath - That's a great summary. In the end it comes to personal preference which is the reason I also mentioned to buy both and return the one you don't like as much.

For those trying to use this with an AR, you will need a riser, there are two types that will work, a medium and a high. The basic cheap UTG one from Amazon is decent.

The Medium height riser below should put you in the zone for absolute co-witness. This means that the iron sights that come with the gun should line up exactly with the red dot.
Pros: only one point at which to aim, failure of your red dot requires no adjustment, you can see if your red dot is off, possibly a slightly better cheekweld
Cons: There is alot of sight in your red dot FOVhttps://www.amazon.ca/UTG-Medium-Profil ... =utg+riser

Conversely there is a high profile riser that should put you in the zone for lower 1/3 cowitness . This means that your iron sights are in the lower 1/3 of your red dot, and your red dot sits central in the scope above it
Pros: There is less sight visible in your red dot
Cons: possibly a bit more of a chin-weld than cheek as the sight is higher, you can't tell if your red dot goes out of calibrationhttps://www.amazon.ca/UTG-Profile-Riser ... =utg+riser

There is no fundamentally better option, it is just personal preference. In a gun like the smith wesson mp sport 2, the front sight post is fixed, so you have to decide if you want to have that front sight post right in the centre of your red dot or in the lower 1/3 of the scope when you look through it. I myself prefer lower 1/3 if the front sight post is fixed, I like a little bit of space underneath the red dot for target identification, but overall I like the ergonomics of absolute if the back-up iron sights are able to be folded down. It's just personal preference and doesn't actually matter alot because these are meant to be shot with both eyes always open, with body facing square to target, so that really it makes very little difference which you choose in terms of overall target visibility.

Updated the pricing, it's now at an unbelievable $96.76 before taxes and then get your $40 rebate!
The 30+ units sold out on Amazon (Red Flag Effect), but they are now replenishing - and as the rebate goes till the end of October, the 2-4 weeks isn't an issue!
Enjoy =)
.

No joke, could be true ,but had it seen by couple of other people ,all see shooting star .
Getting a replacement ,will see once it come thru.

This happens to a lot of people, including myself. It is more obvious in low light condition. When I use it outdoors in bright light condition, i can see a perfect dot. Also, you can try to turn the brightness to a lower setting. This will reduce the effect. I also heard people using some kind of cover on the shooting glasses. Basically it covers most of the glass and only leave a small hole. The small aperture will totally eliminate the blur.